The present invention relates to a switching equipment, and relates more precisely to the identification of data packets in such a switching equipment, that forms part of a telecommunication system, and more particularly the type of switching known as packet switching.
Packet switches are included in a network in which data cells or data packets are transmitted from a transmitter to a receiver, each data cell including an address part and an information part.
A plurality of incoming links are connected to the packet switch via first switch ports, and a plurality of outgoing links are connected to the switch via second switch ports. The switching equipment also includes the control means and coupling means that are needed to control switch functions and operations, so that coupling means pointed out by the control means will connect incoming link: with indicated outgoing link, where indication of the outgoing link, is initiated by signals occurring on the incoming link.
These signals are special signals, and are normally standardized and formed by one or more data cells. Each of the data cells has a constant length of 53 octets, according to CCITT standards, of which 5 octets are included in a so-called Header which contains, among other things, a virtual destination address, and 48 octets which make up a so-called information part.
Several different types of packet switches of the aforedescribed kind are known to the art.
Thus, it is known to use the virtual destination address in the data cell to control the operating functions of a packet switch. To this end, it is necessary to look-up a table in a relevant memory each time information relating to the desired destination address is required for controlling the switch through said control means.
In order to look-up a table, it is normally necessary to establish the address information in the data cell Header, preferably with the aid of a processor assigned to the control means, and transpose the address information to address information that is adapted to the processor and system and then guide the operational functions of the switching equipment with the aid of this processor-adapted address information.
Also known to the art are packet switches that are constructed in accordance .with an ATM system (Asyncronous Transfer Mode). The invention finds particularly suitable application with this type of switching equipments.
Considering the significant features related to the present invention the most relevant prior art is disclosed in the publication U.S. Pat. No. 5,130,984.
Among other publications, related to this technical field, we refer to the publication EP-A1-0 482 550.